Description of Related Art
Many devices and methods have been proposed for performing an anastomosis (graft) between blood vessels. One of the most common surgical procedures carried out today which requires performing an anastomosis is coronary artery bypass grafting (CABG), commonly referred to as bypass surgery. This procedure is used to treat patients suffering from coronary disease in the form of one or more coronary arteries that are partially or completely blocked by stenoses. When blood flow through the coronary arteries is restricted or occluded, the cardiac muscle tissue becomes deprived of adequate blood flow, which eventually results in death of the muscle tissue. Interventional procedures other than bypass surgery, for example, angioplasty and atherectomy, are also used to treat occluded coronary arteries. However, bypass surgery is usually desirable or necessary to treat patients suffering from severe or multiple coronary artery blockages, or when other interventional procedures have been or would likely be unsuccessful.
In order to bypass a blockage in a coronary artery, the surgeon must anastomose a vascular conduit which is in communication with a source of arterial blood to the coronary artery at a location downstream of the blockage. The vascular conduit may be a native artery carrying blood from the patient""s heart, for example, the right or left internal mammary artery (IMA). In such case, the artery may be transected from the patient""s body to provide a free end which is prepared for distal anastomosis to the coronary artery. Alternatively, the IMA may be transected and removed from the body and one end prepared for anastomosis to an arterial blood source and the other to a coronary artery. Further, depending on the number of coronary arteries which are blocked, in addition to using the right and/or left IMA, other vascular conduits may be needed. One end of each conduit is prepared for distal anastomosis to the coronary artery, while the other end is prepared for proximal anastomosis to an arterial blood source, for example, the aorta. The vascular conduits may be harvested from the patient""s body, suitable examples of which include the left or right IMA, inferior epigastric artery, splenic artery, subclavian artery, saphenous vein, etc. Also, animal or synthetic vascular conduits may be used instead of or in addition to those mentioned above.
The most common form of bypass surgery involves bypassing blockages in multiple coronary arteries, e.g., quadruple, five or six-way bypass procedures. As a result, most bypass procedures require a number of vascular conduits to form the necessary anastomoses. However, there is a limited number of native arterial conduits available which may be used by simply attaching one end to a blocked coronary artery. As such, it is usually necessary to use free conduits or grafts, which requires forming an anastomosis at both ends of each conduit, one end to an arterial blood source and the other end to the blocked coronary artery. The patient""s aorta is a desirable arterial blood source to which the proximal end of one or more conduits may be anastomosed. As is the case with all other anastomoses, the surgeon must securely suture the proximal end of each conduit to the patient""s aorta in order to obtain a strong, fluid tight connection, which is a highly technical and time consuming procedure. Nevertheless, when performing bypass surgery via conventional, open-chest procedures in which the patient""s sternum is split and retracted, the surgeon has essentially unobstructed access to the heart and aorta, which reduces the difficulty of forming the proximal anastomoses between the vascular conduits and the patient""s aorta.
During the last several years, however, there has been a movement away from open-chest surgery toward minimally invasive cardiac surgery. Some of the cardiac procedures presently being performed in a minimally invasive manner include, for example, coronary artery bypass, mitral or aortic valve repair or replacement, and septal defect repair. These procedures are typically carried out through incisions made between the ribs, which requires surgeons to operate with considerably less access to the heart and aorta as compared to open-chest procedures. This reduced access to the heart has increased the difficulty and time associated with forming the anastomoses between the vascular conduits and the patient""s arteries, and in particular, the proximal anastomoses between the vascular conduits and the patient""s aorta. More specifically, the already highly technical procedure of suturing the vascular conduits to the aorta or other arterial blood source (as well as to the coronary arteries) is even more difficult when the surgeon is operating through a small port, e.g., an incision 3 or 4 inches in length. As a secure, fluid tight anastomosis is highly desirable in order to provide long term patency of the conduit bypassing the blockage, minimally invasive cardiac surgery presents significant challenges for the surgeon.
The devices and methods used in conventional open-chest cardiac surgery, however, are not always usable or readily adaptable to carry out minimally invasive cardiac surgery. In addition, known devices that use staples to form an anastomosis have had limited acceptance, perhaps due to the fact that suture is the standard in cardiac surgery. Suture is biocompatible, flexible, long-lasting, and well-accepted by cardiac surgeons. As a result, there is a need in the art for improved devices and methods for performing minimally invasive cardiac procedures, and in particular forming anastomoses between vascular conduits and hollow body structures by applying suture through ports or other openings providing limited access to the body structure, and in which the suture is applied in a relatively fast and automated manner to produce a secure anastomosis which provides long term patency.
According to one aspect of the invention, a device is provided for passing one or more needles through tissue. In one preferred embodiment, the device includes a handle, a shaft assembly supporting at least one needle, and an actuator assembly. The needle is supported by the shaft assembly so as to be movable between radially extended and non-extended positions. A protective cover overlies the needle in the radially non-extended position and is movable with respect to the shaft to permit the needle to assume the radially non-extended position. An actuator assembly is operable using one hand to move the cover to allow the needle to assume the extended position and to pass the needle through tissue.
In another preferred embodiment, the device includes a handle and a shaft assembly supporting at least one needle so as to be movable between radially extended and non-extended positions. An actuator moves a ram from a first position to a second position to move the needle to the radially extended position, and also passes the needle through tissue.
In another preferred embodiment, the device includes a handle and a shaft assembly supporting a plurality of needles and a plurality of separate lengths of sutures, the needles being movable between extended and non-extended positions. One end of each length of suture is secured to one of the needles and the other end of each length of suture is located away from the needles.
In more specific preferred embodiments, the handle assembly of the device is preferably generally pistol shaped while the actuator assembly comprises a trigger. This preferred construction permits the device to be operated using one hand by grasping the handle assembly in one hand and moving the trigger with one finger.
In other specific preferred embodiments, the shaft assembly removably supports first and second sets of needles secured to separate lengths of sutures. Each length of suture has a needle from the first set at one end and a needle from the second set at an opposite end. A suture supporting tube is provided on the shaft assembly to organize the lengths of suture and support the second set of needles.
In other specific preferred embodiments, the device is provided with a needle guard in the form of a shield surrounding the needles and movable between expanded and collapsed orientations. The shield expands as the needles assume their radially extended orientation such that the shield is always positioned exterior to the needle. This feature enables the device to be used to pass the needles through tissue adjacent a medical device that includes a portion capable of being punctured, with the shield ensuring that the needles do not engage the portion or component.
According to another aspect of the invention, a method is provided for passing one or more needles through tissue adjacent an opening in the tissue. In one preferred embodiment, the method includes steps of providing at least first and second needles secured to first and second lengths of suture, respectively. The needles are positioned through an opening passing through a tissue wall in a patient""s body, and then are passed through the tissue wall adjacent the opening so that each suture length has a portion extending through the opening and a portion extending through the tissue wall.
In another preferred embodiment, each of the first and second lengths of suture have an end disposed away from the needles to which the length of suture is secured. The first and second needles are positioned inside a patient""s body adjacent an opening in tissue such that the ends of the first and second lengths of suture are located outside an outer surface of the tissue. The ends of the first and second lengths of suture are maintained outside the outer surface of the tissue while the first and second needles are passed into the tissue adjacent the opening, and then out of the tissue to pull the first and second lengths of suture through the tissue.
According to another aspect of the invention, a device is provided for delivering a member adapted to be secured to a patient""s body tissue. The device includes a first component and a second component mounted to the first component, the first and second components being relatively movable. The first component is configured to removably support a member adapted to be secured to a patient""s body tissue, while the second component is configured to hold at least one needle carrying suture for securing the member to the body tissue. The first component is relatively movable with respect to the second component to move the member along the suture into contact with the body tissue.
In one preferred embodiment, the first component is a shaft and the second component is a collar movably mounted on the shaft. A member adapted to be secured to body tissue is supported by the shaft while the collar has an area configured to hold one or more needles each carrying suture extending from the body tissue. After the needles have been placed in the collar so as to pass through the member supported on the shaft, a user imparts relative movement to the shaft and collar to move the shaft and the member along the suture into engagement with the body tissue.
In more specific preferred embodiments, the shaft is in the form of a tube with a hollow interior configured to receive a vascular conduit adapted to be anastomosed to the body tissue. The vascular conduit is guided along the suture into contact with the body tissue by imparting relative movement to the shaft and collar.
According to yet another aspect of the invention, a method is provided for delivering a member adapted to be secured to body tissue. In one preferred embodiment, the method includes steps of placing at least one length of suture through body tissue so that the suture extends away from the body tissue, the suture having an end which carries a needle, and providing a delivery device including first and second components mounted so as to be relatively movable. The member adapted to be secured to the body tissue is positioned on the first component, and the needle carried by the end of the suture is placed through the member into the second component. Relative movement is imparted to the first and second components to move the first component and the member along the suture to a location adjacent the body tissue.
In more specific preferred embodiments, the member is adapted to be secured to the body tissue adjacent an opening in the body tissue, and separate lengths of suture are passed through the body tissue adjacent the opening. The member may be adapted to be secured over the opening in the body tissue, with the lengths of suture passing through the tissue at locations spaced around the opening. For example, the member may be a patch adapted to be attached within a patient""s heart to repair an atrial or ventricular septal defect, or a valve adapted to be attached to a patient""s mitral or aortic valve annulus.
In other specific preferred embodiments, the member is a vascular conduit adapted to be anastomosed to an arterial conduit in the patient""s body, for example, the aorta. Separate lengths of suture are circumferentially disposed around an opening in the wall of the aorta, with the two ends of each length of suture disposed outside the patient""s body and the portion connecting the ends extending through the opening and then though the wall of the aorta. One end of each of suture length is passed through the end of the vascular conduit and the conduit is guided along the suture until it contacts the wall of the aorta over the opening. The ends of each suture length are knotted and the knots pushed against the wall of the aorta to secure the end of the conduit thereto. Alternatively, the sutures may be secured by clips or other fasteners located adjacent the wall of the aorta.
In still another aspect of the invention, an anastomosis system is provided for securing a vascular conduit to a hollow body structure. In the preferred embodiment, the system includes a needle passer comprising a shaft assembly supporting first and second needles and at least one length of suture. An actuator moves at least one of the needles and the length of suture through the tissue of a hollow body. A sealing element configured to be positioned against the end of the vascular conduit is also provided, the sealing element being formed of a material that is able to receive one of the first and second needles. In a specific preferred embodiment, the sealing element is ring-shaped and is formed of a resilient material.
In still another aspect of the invention, a device for use in anastomosing a vascular conduit to a hollow body structure is provided. In the preferred embodiment, the device comprises a sealing element having an opening configured to be aligned with a vascular conduit. The sealing element is formed of a biocompatible material which permits at least one needle to be inserted and passed through the sealing element, thereby permitting suture used to anastomose the vascular conduit to the hollow body structure to be passed through the sealing element.
In still another aspect of the invention, a method for anastomosing a vascular conduit to a hollow body structure so that the vascular conduit is in fluid communication with the interior of the hollow body structure is provided. In the preferred embodiment, the method comprises steps of forming an opening in the tissue of a hollow body structure so that the opening passes into an interior of the body structure, positioning an end of a vascular conduit against the tissue, and attaching the vascular conduit to the tissue so that the vascular conduit is in fluid communication with the interior of the body structure. According to the invention, a sealing element is used to enhance the attachment between the end of the vascular conduit and the tissue.
According to yet another aspect of the invention, a cutting instrument is provided for forming an access opening into a body lumen or cavity, such as a blood vessel. The opening provides access into the lumen or cavity while minimizing damage to the lumen wall, which may occur, for example, during formation of the opening or subsequent introduction of an instrument through the opening. In one preferred embodiment, the cutting instrument comprises a knife having a plurality of cutting surfaces arranged to cut an opening in tissue having a plurality of flaps. The flaps distribute the force exerted on the tissue over several locations so that introducing an instrument through the opening is less likely to propagate a tear along the cut lines.
According to yet another aspect of the invention, a measuring device is provided for gauging the size of a hollow member, such as a vascular conduit. The device includes a pair of jaws provided with tips that contact the opposite inner surfaces of the conduit. The jaws are relatively movable and are biased apart to contact the inner surfaces of the conduit. A scale coupled to the jaws provides a visual indication of the size of the internal dimension of the conduit. In one preferred embodiment, a spring biases first and second jaws apart, and an arm extends from the second jaw and pivotally mounts a rotating scale provided with a series of lumen sizes. The scale is coupled to the first jaw and rotates about the pivot when the first jaw moves into contact with the lumen of the conduit. A mark carried by the second arm indicates the lumen size upon the tips of both jaws contacting the inner lumen surfaces.
According to still another aspect of the invention, a device and method for carrying out a surgical procedure on a hollow body structure through which fluid is flowing is provided. In a preferred embodiment, the method includes steps of forming an opening passing through the hollow body structure which extends from an exterior surface to an interior surface of the hollow body structure, providing a tissue contacting member movable between collapsed and expanded orientations, the tissue contacting member being attached to an elongate support member, and positioning the tissue contacting member in the collapsed orientation through the opening and adjacent the interior surface of the hollow body structure. The tissue contacting member is moved into the expanded orientation and into contact with the interior surface of the hollow body structure, and an instrument is inserted through the opening and into the hollow body structure to carry out a surgical procedure on the hollow body structure, with the tissue contacting member substantially preventing fluid flowing through the hollow body structure from escaping through the opening. In a specific preferred embodiment, the hollow body structure, is a patient""s aorta, and the surgical procedure is carried out to anastomose a vascular conduit to the aorta.